By Danny Kucharsky
MONTREAL -- September 16, 2008 -- Implementation of a single proactive preventive dental program before and during treatment with bisphosphonates can lead to a significant reduction in the incidence of osteonecrosis of the jaw (ONJ), according to the results of a study presented here at the American Society for Bone and Mineral Research (ASBMR) 30th Annual Meeting.
Although it's an uncommon adverse event (<1%), ONJ has been reported in patients receiving complex cancer-treatment regimens, including those containing bisphosphonates, explained Carla Ripamonti, MD, Pain Therapy and Palliative Care Division, National Cancer Institute, Milan, Italy.
Periodontal disease places patients at added risk of ONJ.
Dr. Ripamonti said the study, presented here on September 12 at a poster session, aimed to verify whether the implementation of a preventive dental program could substantially reduce ONJ incidence in clinical practice.
The study had 2 components: retrospective evaluation of ONJ incidence in cancer patients before the application of dental preventive measures, and prospective assessment of ONJ incidence after the implementation of dental preventive care.
The investigators examined 966 cancer patients (73% with metastatic breast cancer) who were treated at the National Cancer Institute in Milan from 1999 to 2007. Patients received zoledronic acid (n = 244), pamidronate (n = 600), pamidronate followed by zoledronic acid (n = 79), or clodronate alone or with pamidronate (n = 43).
The group of patients who did not receive any preventive dental examinations prior to treatment-retrospective assessment (PRE group) involved 812 patients (median follow-up time = 9 months) treated with bisphosphonates. The group of patients who had completed preventive dental examinations every 6 months and other dental procedures prior to treatment (POST group) involved 154 patients (median follow-up time = 11 months) also treated with bisphosphonates.
ONJ was observed in 2.9% (n = 28) of the overall cohort, the researchers found. The PRE group experienced a 3.2% incidence of ONJ compared to 1.3% in the POST group, showing that dental preventive measures reduced the risk of ONJ by 60% (although this figure was nonsignificant statistically).
Dr. Ripamonti noted that there was a "remarkable" reduction of 76% in overall ONJ incidence rate observed in the POST group as compared to the PRE group, using per-protocol analyses. Reductions of 81% were seen in patients treated with zoledronic acid and 86% in patients treated with zoledronic acid and pamidronate.
"Data from this trial clearly illustrate that ONJ can be effectively prevented and managed," Dr. Ripamonti concluded. She added that the results underscore the importance of implementing preventive dental care in all patients undergoing treatment with bisphosphonates.
[Presentation title: Application of Preventive Measures Minimizes the Occurrence of Osteonecrosis of the Jaw in Patients With Bone Loss Treated With Bisphosphonates: A Single-Institution Series. Abstract F281]
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